Hand tool for crimping electrical connectors



Aug. 10, 1965 K. J. BATCHELLER HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS Filed Feb. 15, 1962 FIG? INVENTOR. KENT J BATCHELLER ATTORNEYS United States Patent M 3,199,336 HAND TOQL FER CRIMPING ELECTRICAL CONNECTORS Kent J. Batcheller, Newton Highlands, Newton, Mass assiguor to The Thomas & Eetts Co., Inc, Elizabeth, N..I., a corporation of New Jersey Filed Feb. 15, 1962, Ser. No. 173,432 1 Claim. (Cl. 72-413) This invention relates to a hand tool for crimping the wire-gripping portion of an electrical connector or the like so that the wire is tightly gripped to make a strong joint and a good electrical contact between the wire and the connector. It is an object of the invention to provide a crimping tool such that when a connector is being crimped onto a wire of a size for which the tool is adjusted, the crimping elements must be moved to a predetermined nearness to each other before the joined wire and connector can be released from the tool. If the dimensions of the connectors and of the wires are constant, this feature ensures that a sufficiently tight joint is made each time the tool is operated. As hereinafter described, apressing element is moved upward toward a fixed element by a toggle connection with the handles of the tool. A ratchet and pawl device is employed to prevent downward movement of the pressing element until it has reached a point of nearness to the fixed element for which the tool has been adjusted. When the pressing element reaches that point the pawl releases the ratchet and the pressing element can be retracted to permit the removal of the work piece.

For a more complete understanding of the invention, reference may be had to the following description thereof and to the drawings, of which FIGURE 1 is a perspective view of the operating portion of a tool embodying the invention, portions being broken away to show inner parts;

FIGURE 2 is a fragmentary elevational view of the handles and links, showing the springs for pressing the handles apart;

FIGURE 3 is similar to FIGURE 2 but shows the parts in a different position; and

FIGURES 4 to 7 are enlarged diagrammatic elevations of the ratchet and pawl device in successive positions of operation.

The tool shown on the drawing comprises a head 10 to which a pair of handles 12, 14 are attached by toggle links 16, 18 respectively. The handles are pivotally joined to each other at their upper ends by a pivot pin 26 which also passes through the bifurcated lower end of a vertical plunger 22 which extends up through the base 24 of the head 10 and carries a detachable anvil 26 on its upper end. The head It? has an overhanging portion 30 which carries a detachable crimping die 32 above the anvil 26, the die and anvil cooperating, when brought together by rising movement of the plunger 22, to crimp the wire-gripping portion of an electrical connector or the like about a wire.

It is important that the work piece be strongly pressed in order to produce a tight connection. For this purpose the tool is constructed in such a way that when it is being operated to press the anvil 26 up toward the die 32, the plunger cannot be lowered until it has been raised to a 3,l9,336 Patented Aug. 10, 1965 predetermined nearness to the die 32. The plunger is provided with an upper lateral notch 34 and a lower notch 36. Between these notches are ratchet teeth 38 engageable by a pawl 40 when the plunger 22 rises. The pawl 40 is pivotally mounted as at 42 in a forked retainer 44 within the base 24, the lower part of the base being bifurcated to receive the pawl 40 and the upper ends of the links 16, 18. A spring 46 having one end secured to the retainer 44 and the other end in a notch in the pawl tends to retain the pawl yieldingly in a horizontal position as shown in FIGURE 4. The pawl 49 can be adjusted toward or from the plunger 22 by a short screw 48 which bears against an end of the retainer 44 to push it toward the plunger 22 against the pressure of a spring 50 which surrounds part of the retainer 44. A locking screw 52 extends across the bifurcation in the base 24 to bind the screw 48 in any position of adjustment to which the screw has been turned.

As shown in FIGURE 4, the tip of the pawl 40 normally projects into the notch 34 slightly beyond the line of ratchet teeth 38. When the tool is operated to push the plunger upward, the pawl 40 is tilted when its tip rides out of the recess 34 to engage the teeth of the ratchet 38. This prevents downward movement of the plunger until the plunger has moved far enough upward to carry the lowest tooth of the ratchet 38 past the tip of the pawl so that the pawl can be rocked by the spring 46 to its normal horizontal position with its tip in the recess 36. The plunger can now be lowered by swinging the handles 12, 14 apart, the pawl 46 being tilted downward as in FIGURE 7 to let the tip ride over the teeth of the ratchet 38.

When the plunger has reached the top of its stroke and is released for downward movement, the handles are pushed apart by springs 60. As shown, these springs are identical, one being supplied for each handle. The upper end portion of each spring bears against the pivot pin 20. The lower end portion is curled into an approximate semi-circle as at 64. It then passes through a small hole in an end lug 66 on the lower end of the link 16 or 18 and extends across the end face of the link as at 68. The extremity is bent up to bear in a small groove in a side face of the link as at 70. The springs 6%) are biased to press strongly against the pin 20 within the bifurcated lower end of the plunger 22. In pressing the handles apart from the closed position shown in FIGURE 3 to the open position shown in FIGURE 2, the springs 60 undergo very little change of shape as can be seen by comparing FIG- URES 2 and 3. This means that the useful life of these springs is practically without limit.

I claim:

A hand tool for pressing small objects, said tool comprising a head having a base and a portion overhanging the base, a plunger extending slidably through said base and reciprocable toward and from said overhanging portion, a pair of handles pivotally attached to the lower end of said plunger, toggle links attached at one end to said head and at the other end to the respective handles, means operating when said plunger is moving toward said overhanging portion of the head for preventing reverse movement of the plunger until it has come within a predetermined distance of said overhanging portion, said reverse movement preventing means including two spaced recesses 3 4 with a series of teeth between them on a side of said 'Referenees Cited by the Examiner plunger and a pawl pivotally mounted in said head in UNITED STATES PATENTS position to engage said teeth, and means accessible from outside of said head for adjusting said pawl toward and 2,784,621 3/57 Khnglerfrom said plunger, said adjusting means including a re- 5 2,928,299 3/60 Fuuertainer in said head in which said pawl is pivotally 2974551 3/61 PQWCH X mounted, a spring in said head pressing said retainer and 3053112 9/62 Kungler pawl away from said plunger, and a screw within said FOREIGN PATENTS ead and bearing against an end of said retainer, said 6031213 1/35 Gannanyscrew being adjustable to determine the position of the 10 retainer relative to the plunger. WILLIAM FELDMAN, Primary Examiner. 

